1. Field of the Invention
This invention relates to a mirror assembly attachment for the distal end of a borescope insertion tube, and more particularly to a self-contained motorized assembly for rotating a mirror and providing a 360 degree side-looking view in a standard video borescope.
2. Description of the Prior Art
In many industrial applications where borescopes are used, they have to be inserted a considerable distance into inaccessible cavities for viewing the interior thereof. In long, narrow cavities, and particularly in pipes, it is sometimes difficult to distinguish points of interest on the walls thereof when looking straight ahead through the distal end of the borescope insertion tube.
Accordingly, for some time it has been a common practice to provide angled mirrors for allowing viewing at an angle to the axis of the insertion tube of the borescope including fixed angular mirrors at the end of a standard borescope and various rotated mirrors, all of which to a degree have allowed viewing of the interior surface walls of the enclosure adjacent the tip of the insertion tube. An angled mirror rotating about the axis of the insertion tube produces a so-called side viewing capability for looking at the walls of a pipe, for instance, as the insertion tube is traversed through the pipe. Rotatable mirrors of this type have been used to reflect the source of light in the distal end of the insertion tube onto the wall of the tube, as the mirror rotates and to pick up the reflected video image so as to scan the entire inside circumference of the pipe as the insertion tube is moved therethrough.
Since in some installations the borescope insertion tube can have a length of ten to fifty feet, it is important that this adaptor, when mounted on the distal end of a borescope insertion tube be securely fixed thereto so it cannot be accidentally dislodged or disengaged and lost in the interior of a narrow elongated cavity such as a steam pipe.
U.S. Pat. No. 5,122,900 of common assignee herewith discloses a self-contained motorized mirror assembly that can be removably mounted on the distal end of a borescope insertion tube. This assembly has a self-locking attachment, and an integral on/off switch and battery cap assembly for controlling power to the motor for the rotatable mirror. With this device rotatable mirrors are easily interchanged. However the mirror assembly is larger than the distal portion of the insertion tube. Also the switching mechanism is involved with the battery compartment, and it is not feasible to change batteries without disturbing the switching mechanism.